Oil level detecting device for a compressor and an air conditioning system having the same

ABSTRACT

An oil level detecting device for a compressor and an air conditioning system having the same are provided. The oil level detecting device may be provided in a compressor including a compression device that introduces and compresses a working fluid, a driving device mechanically connected to the compression device that operates the compression device, and a case that accommodates the compression device and the driving device thereinside and having an oil storage space that stores oil at a lower portion thereof. The oil level detecting device may include a detector including a supporting portion configured to be attached to the case and a detecting portion that protrudes inside the case. At least one property of the detecting portion may vary according to an oil level inside the case. The oil level detecting device may also include a signal processor including an electronic element having at least one reference property. The signal processor may compare the at least one property of the detecting portion with the at least one reference property of the electronic element and outputs a control signal according to the result.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a Reissue Application of prior U.S. Pat. No.8,733,116 issued May 27, 2014 (U.S. patent application Ser. No.12/958,874 filed Dec. 2, 2010), which claims priority under 35 U.S.C.§119 to Korean Application No. 10-2010-0030122 filed in Korea on Apr. 1,2010, whose entire disclosure(s) is/are disclosures are herebyincorporated by reference.

BACKGROUND

1. Field

An oil level detecting device for a compressor and an air conditioningsystem having the same are disclosed herein.

2. Background

Oil level detecting devices for compressors and air conditioning systemshaving the same are known. However, they suffer from variousdisadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the followingdrawings in which like reference numerals refer to like elements, andwherein:

FIG. 1 is a cross-sectional view of a compressor having an oil leveldetecting device according to an embodiment;

FIG. 2 is a perspective view of the oil level detecting device of FIG. 1according to an embodiment;

FIG. 3 is a perspective view of an oil level detecting device accordingto another embodiment;

FIG. 4 is a perspective view of a controller including a signalprocessor according to an embodiment;

FIG. 5 is a circuit diagram of the signal processor of FIG. 4; and

FIG. 6 is a block diagram of an air conditioning system according to anembodiment.

DETAILED DESCRIPTION

A compressor, as broadly described and embodied herein, may include adrive motor that provides a driving force to a compression device tocompress refrigerant while operating in conjunction with the drivemotor. The compressor may be categorized as, for example, areciprocating type, a scroll type, a rotary type, or a vibration type,depending on the method by which the refrigerant is compressed.Reciprocating type, scroll type, and rotary type compressors use arotary motion of the drive motor, while vibration type compressors use areciprocating motion of the drive motor.

The drive motor of a rotary type compressor may be provided with acrankshaft that transfers the rotary motion of the drive motor to thecompression device. For example, the drive motor of the rotarycompressor may include a stator fixed to a container or case, a rotorpositioned in the stator with a predetermined gap therebetween to rotatein interaction with the stator, and a crankshaft connected to the rotorto transfer rotary power to the compression device. In addition, thecompression device may be combined with the crankshaft to suction,compress, and discharge refrigerant while rotating inside a cylinder. Aplurality of bearing members may be provided to form a compression spacebetween the crank shaft and the compression device, and may also supportthe compression device.

In the compressor having the foregoing structure, the refrigerant may becompressed by rotating the compression device with rotary motiongenerated by the drive device. The compressor may be provided with anoil supply device to supply oil to the compression device that mayfacilitate the rotation of the compression device as well as easilydissipate heat generated during operation of the drive device. The oilsupply device may be provided at a lower end portion of the crankshaft.The oil may be stored in a lower portion of the container, or case, andmay be pumped through an oil flow path formed inside the crankshaft bythe rotation of the crankshaft. The pumped oil may then be supplied toeach component inside the compressor.

In compressors of various air conditioning systems, the oil flow path,or pipe, in which the working fluid flows may be lengthened, requiringan increased amount of oil to operate the compressor. Thus, it may bedifficult to estimate when, where, and how much oil will remain, andaccordingly, it may be difficult to maintain the oil level inside eachcompressor in an appropriate condition or level. As a result, the oillevel in the oil storage space may become irregular and may vary outsideof acceptable levels during operation of the respective compressor, evenwhen the oil levels were within a suitable range at an initial stage ofthe operation.

Therefore, it may be necessary to continuously check the oil levelinside each compressor during operation of the air conditioner. If it isdetermined that the oil level is not in an appropriate condition, thenan oil collecting operation to add oil to the compressor may beperformed. Conventionally, it is not easy to check the oil level in eachcompressor, and therefore, the oil collecting operation may be performedat a predetermined period of time regardless of the actual oil level.Performing the oil collecting operation irrespective of the actual oillevels may be inefficient as energy is wasted during unnecessary oilcollecting operations.

To overcome this problem, an oil level sensor may be provided in thecompressor to measure the oil level to determine whether an oilcollecting operation is necessary. In such a system, the number ofunnecessary oil collecting operations may be reduced, resulting indecreased energy consumption as well as decreased compressor downtime.

FIG. 1 is a cross-sectional view of a compressor having an oil leveldetecting device according to an embodiment, and FIG. 2 is a perspectiveview of the oil level detecting device of FIG. 1 according to anembodiment. Simply for ease of explanation, this embodiment is describedwith reference to a scroll compressor, but the embodiments are notlimited thereto. It will be apparent to those skilled in the art thatthe embodiments disclosed herein may be applied to any type ofcompressor, in particular, any type of compressor in which oil isprovided at a lower end portion of a rotating shaft.

Referring to FIGS. 1 and 2, a main frame 120 and a sub-frame 130 may beprovided inside a container or case 110, and a drive device 140, forexample, a drive motor, may be provided between the main frame 120 andthe sub-frame 130. A compression device may be provided at an upper sideof the main frame 120 and combined with the drive motor 140 thatcompresses a working fluid, for example, a refrigerant. The compressiondevice may include a fixed scroll 150 and an orbiting scroll 160.

The drive motor 140 may include a stator 141, which may be wound with acoil, a rotor 142 rotatably inserted in the stator 141, and a rotatingshaft 143 attached to a center of the rotor 142 that that transfersrotary force to a compression mechanism. A driving pin portion 144 maybe formed to protrude at an upper end of the rotating shaft 143. Thedriving pin portion 144 may be formed adjacent to a rotational axis ofthe rotating shaft 143. That is, the driving pin portion 144 may bepositioned away from a rotational center of the rotating shaft 143.

The compression mechanism may include a fixed scroll 150 fixed to anupper surface of the main frame 120, an orbiting scroll 160 placed onthe upper surface of the main frame 120 and engaged with the fixedscroll 150, and an Oldham ring 170 disposed between the orbiting scroll160 and the main frame 120 that prevents the rotation of the orbitingscroll 160. A fixed wrap 151 may be spirally wound and formed on thefixed scroll 150. Further, an orbiting wrap 161 may be spirally woundand formed on the orbiting scroll 160. The fixed wrap 151 together withthe orbiting wrap 161 may form a compression chamber (P). A boss portion162 may be formed to protrude at a bottom surface of the orbiting scroll160, for example, a lateral surface opposite the orbiting wrap 161. Theboss portion 162 may engage the rotating shaft 143 to receive a rotaryforce therefrom.

A sliding bush 163 may be combined with the driving pin portion 144 ofthe rotating shaft 143 to slide in a radial direction. The sliding bush163 may be combined with the boss portion 162 of the orbiting scroll 160to slide in a rotating direction. An external diameter of the slidingbush 163 may be formed to be same as an internal diameter of the bossportion 162 of the orbiting scroll 160, to thereby reduce frictionbetween the rotating shaft 143 and the orbiting scroll 160. Further, amain frame bush 122 may be provided on an inside surface of the mainframe 120 to reduce friction between the rotating shaft 143 and mainframe 120. Oil may be supplied by an oil feeder 180 provided at a lowerend portion of the rotating shaft 143 to lubricate each of the bushes122, 163.

For example, the oil may be stored in a oil storage space formed by aninner surface of a base 112 of the container 110. The oil may be pumpedfrom the oil storage space and supplied to the compression devicethrough an oil flow path 143a formed inside the rotating shaft 143. Theoil feeder 180, provided at a lower end portion of the oil flow path143a, may rotate with the rotating shaft 143 to pump the oil from theoil storage space into the oil flow path 143a. The pumped oil may thenbe supplied to the compression device positioned at an upper portion ofthe oil flow path 143a.

To ensure that the oil is supplied to the oil feeder 180, oil should bemaintained at an appropriate level. As discussed previously, the oillevel may vary during operation of the compressor. The variation of oillevel may be an absolute variation, which may be caused by a loss ofoil, for example, by leakage of oil, or a temporary variation, which maybe caused during operation of the compressor. For example, the oil levelmay temporarily increase or decrease during operation according to achange in an operational speed of the compressor. Accordingly, the oillevel should be maintained at an appropriate level to account for bothabsolute and temporary variations to ensure normal operation of thecompressor.

An oil level detecting device that detects the oil level in real timemay include a detector 200, provided in the container 110, and acontroller 250. The controller 250 may monitor the oil level usingmeasurements obtained from the detector 200. The controller 250 may beprovided on an outer wall of the container 110. Alternatively, thecontroller 250 may be provided at a remote location, for example, in amanagement facility or control room.

The detector 200 may include a pair of electrodes 210 that may protrudeinto the container 110. A supporting plate 220 may be provided tosupport the electrodes 210 and allow it to pass through the case 110into the compressor. The supporting plate 220 may be inserted into amounting hole 114 formed through the container 110 and may be attachedthereto by, for example, welding or another appropriate method. Thesupporting plate 220 may be attached to the case 110 such that thesupporting plate 220 is flush with an outer surface of the case 110.Further, the supporting plate 220 may include a flange 222 thatprotrudes from an outer circumference of the supporting plate 220. Aflange seating portion 116 having a diameter greater than the mountinghole 114 may be formed at an outer circumference of the mounting hole114. The flange 222 may then be seated on the flange seating portion 116and may be, for example, welded to the case.

Referring to FIG. 2, the detector 200 may include a pair of electrodeplates 210 disposed inside the container 110. The electrode plates 210may extend into the oil storage space such that variation in oil levelsmay be detected by the electrode plates 210. The electrode plates 210may be mounted to an interior side wall of the container by beingconnected to the supporting plate 220.

Each of the electrode plates 210 may include a conductive plate 212,which may be formed of a conductive material, and a pin 214, which maybe formed to be integral with the conductive plate 212. As shown in FIG.2, the pins 214 may have a width that is smaller than a width of theconductive plates 212. The pair of conductive plates 212 may be disposedto be adjacent to each other having a predescribed spacing therebetween.Thus, the pair of conductive plates 212 may serve as a capacitor havinga capacitance that may vary according to variations in the oil level.For example, the capacitance between the electrode plates 210 may be apredetermined value when the oil level is below the electrode plates210. As the oil level rises to contact the electrode plates 210, thepresence of the oil may vary the capacitance of the electrode plates210. Accordingly, each of the electrode plates 210 may be disposed atappropriate positions corresponding to an upper and lower limit of theoil level. The incremental changes in the capacitance may then bemonitored to detect whether the oil level is outside an acceptablerange.

Simply for ease of explanation, the conductive plate 212 and pin 214 ofthe electrode plate 210 have been described as being integrally formed.In another embodiment, as illustrated in FIG. 3, a conductive plate 212′and a pin 214′ may be individually molded, then bonded to each otherusing a method, such as, for example welding, or another appropriatemethod. Moreover, the electrode plates 210 may be formed such that theconductive plate 212 and the pin 214 are the same width. In such a case,the conductive plate 212 and the pin 214 may be formed such that theyare integrally formed as a single piece or as separate parts that arebonded together.

FIG. 4 is a perspective view of a controller including a signalprocessor to an embodiment. The controller 250 of FIG. 4 may beconnected to the detector 200. The controller 250 may be electricallyconnected to the detector 200 by a connector 240. The connector 240 maybe attached to lead wires 230, which may be connected to pins 214 of thedetector 200. A printed circuit board including a signal processor maybe provided in the controller 250. The controller 250 may also includetwo LEDs 252, 254 provided on an outer surface thereof.

The LEDs 252, 254 may serve as a display to visually display thedetected oil level. More specifically, the LED 252 may indicate that theoil level is in a normal condition, and the LED 254 may indicate thatthe oil level is not in a normal condition. Each LED may have adifferent color, thereby allowing the user to easily recognize the oillevel visually.

FIG. 5 is a circuit diagram of the signal processor of FIG. 4 accordingto an embodiment. The signal processor 500 of FIG. 5 may be provided ina printed circuit board. The signal processor 500 may include amicrocomputer 260 connected to the detector 200 that receives acapacitance value from the detector 200 for comparison to a referenceproperty of an electric element.

The microcomputer 260 may be provided with six terminals. DC voltage(VDD) may be applied to a first terminal, and a noise filter may beconnected to a second terminal. Further, the detector 200 may beconnected to a third terminal, and an electric element, for example, areference capacitor 264 having a predetermined capacitance, may beconnected to a fourth terminal. The capacitance of the referencecapacitor 264 may be the same as the capacitance of the detectingportion 210 (electrode plates) of the detector 200 when the oil level isin a normal condition. The microcomputer 260 may check the oil level byusing a measured capacitance of the detecting portion 210 as an inputvalue, and using the capacitance of the reference capacitor 264 as areference value for comparison to the measured value.

A fifth terminal of the microcomputer 260 may be grounded, and a sixthterminal may be an output terminal. The output terminal may be connectedto a third terminal of a three-pin header 262 corresponding to an outputterminal provided on the controller 250. A second terminal of thethree-pin header 262 may be grounded, and the first terminal may beconnected to a DC voltage (VDD). In addition, the three-pin header 262may be connected to the controller 250 to provide information about theoil level.

The compressor as illustrated in FIG. 1 may be implemented in an airconditioning system having a plurality of compressors and indoor units.Examples of an air conditioner having a plurality of compressors andmethods of controlling the same are disclosed in co-pending applicationSer. No. 12/958,915, now abandoned, which is hereby incorporated byreference.

Referring to FIG. 6, the air conditioner may include two compressors101, 102, three indoor heat exchangers 300, 310, 320, expansion valves302, 312, 322 connected to the indoor heat exchangers, respectively, anoutdoor heat exchanger 330, a 4-way valve 340, and an accumulator 350that supplies refrigerant to each of the compressors 101, 102. Each ofthe compressors 101, 102 may be provided with the above discusseddetector 200 and controller 250. An indoor unit in an air conditioningsystem may include an indoor heat exchanger and an expansion valve tocontrol the flow rate of working fluid to the indoor heat exchanger. Thecontroller 250 may transmit control signals to a system controller 360that controls the operation of the air conditioner. Further, the systemcontroller 360 may control various valves or fans in addition to theother elements of the air conditioning system as illustrated in FIG. 6.

Hereinafter an operation of the signal processor 500 will be described.If the oil level is in a normal condition or within an acceptable range,then the capacitance of the detector 200 may be similar to thecapacitance of the reference capacitor 264. In this case, a voltagesimilar to the DC voltage (VDD) may be output through the sixthterminal, thus a voltage difference between the first and thirdterminals may become “0”. On the contrary, if the oil level is not in anormal condition or is outside an acceptable range, then the capacitanceof the detector 200 may have deviated from the reference capacitor 264.In this case, the voltage of the sixth terminal may become “0.”Accordingly, a voltage difference between the first and third terminalsof the three-pin header 262 may correspond to VDD. The voltagedifference output from the three-pin header 262 may be transmitted tothe system controller 360 as a control signal. The system controller 360may control the operation of the compressor or the indoor unit accordingto the received control signal. If it is determined that oil is not atan appropriate level, the system controller 360 may adjust the oil levelto maintain an appropriate condition. For example, if the oil level isdetermined to be below a normal range, the controller 360 may implementan oil collecting operation to adjust the oil level.

Simply for ease of explanation, the values for voltages output at thesixth terminal have been described as being VDD when the oil level iswithin an acceptable range, and “0” when the oil level is outside theacceptable range. However, the voltage output at the sixth terminal isnot limited to the foregoing values and may be configured to have anopposite value. For example, when the oil level is in a normalcondition, the output voltage may become “0”, but otherwise it maybecome “VDD.”

Further, a voltage in proportion to a difference between the capacitanceof the reference capacitor 264 and the capacitance of the detector 200may be output at the sixth terminal. For example, it may be possible notonly to merely check whether the oil level is in a normal condition, butalso to check an amount in which the oil level is outside a normalcondition or range, thereby allowing a more precise control of the oillevels.

Moreover, the microcomputer 260 may monitor the oil level in real timewhile simplifying the configuration of the oil level detecting device.For example, complicated processes, such as converting a value measuredfrom the detecting portion to compare the value with a reference valuerecorded in memory, and the like, may be eliminated.

In addition, a property of a detecting portion used to detect the oillevel may not be necessarily limited to a capacitance as describedabove, but any property that varies with respect to the oil level may beused. For example, in another embodiment the detecting portion may beconfigured such that a resistance value may vary with respect to the oillevel. In this embodiment, an electronic element having a referenceresistance value may be provided in the signal processor to be comparedto a measured resistance value of the detecting portion.

In another embodiment, a plurality of electronic elements may beprovided in the signal processor. In this embodiment, each of theplurality of electronic elements may be configured to correspond to adifferent oil level. Thus, a greater predetermined range of oil levelsmay be monitored.

According to an embodiment, there is provided an oil level detectingunit, which may be provided in a compressor including a compression unitthat introduces and compresses a working fluid, a driving unitmechanically connected to the compression unit that operates thecompression unit, and a case that accommodates the compression unit anddriving unit thereinside and having an oil storage space to store oil ata lower portion thereof. The oil level detecting unit may include adetector including a supporting portion welded to the case and adetecting portion disposed to be protruded inside the case in which theproperty thereof varies according to the oil level, and a signalprocessor comprising an electronic element having a reference propertythat compares the property of the detecting portion with the referenceproperty of the electronic element and output a control signal accordingto the result.

According to this embodiment, an oil level is not determined byconverting a value measured by the detecting portion and comparing thevalue with a numerical value recorded in the storage means, such as amemory, but rather, the detecting portion may be configured to have aproperty that varies according to the oil level, and the signalprocessor may include an electronic element having the propertycorresponding to the property of the detecting portion when the oillevel inside the case is at a specific level, for example, at adesirable level, and thus, the two properties, the property of thedetecting portion and the property of the electronic element, may bedirectly compared to each other without having an additional conversionprocess, thereby simplifying the configuration of a signal processor.

Further, a plurality of electronic elements may be provided therein, andthe property of each electronic element may correspond to a specific oillevel inside the compressor. Accordingly, it may be possible to checkwhether the oil level is positioned within a specific range.

Moreover, the property may be an arbitrary value that an electronicelement may have, or the property may be any physical property, such asa resistance or capacitance. In one embodiment, the detecting portionmay have a capacitance that varies according to the oil level, and theelectronic element may be a capacitor having a capacitance correspondingto a reference value. On the other hand, the detecting portion mayinclude a pair of electrode plates that extends to an inside of the oilstorage space, and in this case, a capacitance of the detecting portionmay be changed according to the amount of oil existing between theelectrode plates. In addition, the oil level detecting unit may furtherinclude a display operated by a control signal of the signal processorto visually or acoustically indicate the oil level.

Further, the supporting portion may include a supporting plate weldedinside a mounting hole formed at a wall surface of the case, and thedetecting portion may include a pair of electrode plates connected tothe supporting plate. A flange may be formed at an outer circumferenceof the supporting portion, and a flange seating portion, on which theflange may be contacted, may be formed at an outer circumference of themounting hole. In other words, the flange may be seated on a flangeseating portion positioned at an outer circumference of the mountinghole to be maintained at the desired position, thereby facilitating themounting process. The supporting plate may be made of a metallicmaterial, and the supporting plate and the electrode may be combinedwith each other by interposing an insulation material therebetween.

The electrode plate may include a conductive plate positioned at aninside of the oil storage space and a pin that extends from theconductive plate by penetrating the supporting portion. Further, thedisplay may include a light emitter that emits different colorsaccording to a control signal output from the signal processor.

According to another embodiment, there is provided an air conditioner,including one or more compressors that may include a compression unitthat introduces and compresses a working fluid, a driving unitmechanically connected to the compression unit that operates thecompression unit, a case that accommodates the compression unit anddriving unit thereinside and having an oil storage space to store oil ata lower portion thereof, and an oil level detecting unit fixed to thecase; an indoor unit that performs cooling or heating using refrigerantdischarged from the compressor; and a controller that controls theoperation of the compressor and the indoor unit. The detector oil leveldetecting unit may include a detector including a supporting portionwelded to the case and a detecting portion disposed to protrude insidethe case in which the property thereof varies according to the oillevel; and a signal processor including an electronic element having areference property, that compares the property of the detecting portionwith the reference property of the electronic element and outputs acontrol signal according to the result. The controller may control theoperation of the compressor or the indoor unit according to a controlsignal transmitted from the signal processor, to control the oil levelto be in an appropriate condition. The indoor unit may be defined tohave a indoor heat exchanger and an expansion valve.

According to this embodiment, the oil level may be checked in real timeby comparing the property of the detecting portion with the property ofthe electronic element as a reference value, and thus, the configurationof the signal processor may be simplified, thereby reducing the unitcost of the product, as well as enhancing reliability.

According to another embodiment, an oil level detecting device may beprovided in a compressor. The compressor may include a compressiondevice that introduces and compresses a working fluid, a drive devicemechanically connected to the compression device that operates thecompression device, and a case that accommodates the compression deviceand the driving device thereinside and having an oil storage space thatstores oil at a lower portion thereof. The oil level detecting devicemay include a detector including a supporting portion configured to beattached to the case of the compressor and a detecting portion thatprotrudes inside the case, wherein at least one property of thedetecting portion may vary according to an oil level inside the case,and a signal processor including an electronic element having at leastone reference property, that compares the at least one property of thedetecting portion with the at least one reference property of theelectronic element and outputs a control signal according to the result.

The supporting portion may be welded to the case of the compressor.Further, a surface of the supporting portion may be flush with an outersurface of the case. Furthermore, the at least one property of thedetecting portion may be a capacitance of the detecting portion, whichmay vary according to the oil level, and the electronic element may be acapacitor and the at least one reference property may include apredetermined capacitance of the electronic element. The predeterminedcapacitance of the capacitor may be the same as the capacitance of thedetecting portion when the oil level inside the case is in anappropriate condition. Alternatively, when the oil level inside the caseis in an appropriate condition, the capacitance of the detecting portionmay be within a predetermined range of the predetermined capacitance ofthe capacitor.

The detecting portion may include a pair of electrode plates thatextends into an inside of the oil storage space. Further, the pair ofelectrode plates may extend perpendicular to an inner wall of the case.

The oil level detecting device of this embodiment may further include adisplay operated by a control signal of the signal processor thatvisually or acoustically displays the oil level. The display may includea light emitter that emits different colors according to a controlsignal output from the signal processor.

The supporting portion may include a supporting plate welded inside amounting hole formed at a wall surface of the case, and the detectingportion may include a pair of electrode plates connected to thesupporting plate. A flange may be formed at an outer circumference ofthe supporting portion, and a flange seating portion, on which theflange may be positioned, may be formed at an outer circumference of themounting hole. Each of the plurality of electrode plates may include aconductive plate positioned at an inside of the oil storage space, and apin that extends from the conductive plate to the supporting portion.The pins of the plurality of electrode plates may extend perpendicularto a wall surface of the case. Further, the conductive plates of theplurality of electrode plates may extend perpendicular to a wall surfaceof the case. The pin may be formed integral with the conductive plate,and the conductive plate may be formed wider than the pin.

According to another embodiment, an air conditioner may be providedwhich may include a plurality of compressors including a compressiondevice that introduces and compresses a working fluid, a driving devicemechanically connected to the compression device that operates thecompression device, a case that accommodates the compression device andthe driving device thereinside and having an oil storage space thatstores oil at a lower portion thereof, and an oil level detecting devicefixed to the case; an indoor device that performs cooling or heatingusing refrigerant discharged from the plurality of compressors, theindoor device comprising an indoor heat exchanger and an expansionvalve; and a controller that controls an operation of the plurality ofcompressors or the indoor device. The oil level detecting device mayinclude a detector including a supporting portion configured to beattached to the case and a detecting portion that protrudes inside thecase, wherein at least one property of the detecting portion may varyaccording to an oil level within the case; and a signal processorincluding an electronic element having at least one reference property,the signal processor comparing the at least one property of thedetecting portion with the at least one reference property of theelectronic element and outputting a control signal according to theresult. The controller may control the operation of the plurality ofcompressors or the indoor device according to the control signaltransmitted from the signal processor to control the oil level insidethe case to be in an appropriate condition.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the invention. The appearancesof such phrases in various places in the specification are notnecessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. An oil level detecting device provided in acompressor, the compressor comprising a compression device thatintroduces and compresses a working fluid, a drive device mechanicallyconnected to the compression device that operates the compressiondevice, and a case that accommodates the compression device and thedriving device thereinside and having an oil storage space that storesoil at a lower portion thereof, the oil level detecting devicecomprising: a detector comprising a supporting portion configured to beattached to the case of the compressor and a detecting portion thatprotrudes inside the case, wherein at least one property of thedetecting portion varies according to an oil level inside the case; anda signal processor comprising an electronic element having at least onereference property, that compares the at least one property of thedetecting portion with the at least one reference property of theelectronic element and outputs a control signal according to the result,wherein the supporting portion comprises a supporting plate installedinside a mounting hole formed at a wall surface of the case, and thedetecting portion comprises a pair of electrode plates connected to thesupporting plate, and wherein each of the plurality of electrode platescomprises: a conductive plate positioned at an inside of the oil storagespace; and a pin that extends from the conductive plate to thesupporting portion so as to electrically connect the conductive plate tothe signal processor through the supporting plate, the pin being formedas a rigid body so as to support the conductive plate respective to thesupporting plate.
 2. The oil level detecting device of claim 1, whereinthe supporting portion is welded to the case of the compressor.
 3. Theoil level detecting device of claim 1, wherein a surface of thesupporting portion is flush with an outer surface of the case.
 4. Theoil level detecting device of claim 1, wherein the at least one propertyof the detecting portion comprises a capacitance of the detectingportion which varies according to the oil level, and wherein theelectronic element is a capacitor and the at least one referenceproperty comprises a predetermined capacitance of the electronicelement.
 5. The oil level detecting device of claim 4, wherein thepredetermined capacitance of the capacitor is the same as thecapacitance of the detecting portion when the oil level inside the caseis in an appropriate condition.
 6. The oil level detecting device ofclaim 4, wherein when the oil level inside the case is in an appropriatecondition the capacitance of the detecting portion is within apredetermined range of the predetermined capacitance of the capacitor.7. The oil level detecting device of claim 4, wherein the detectingportion comprises a pair of electrode plates that extends into an insideof the oil storage space.
 8. The oil level detecting device of claim 7,wherein the pair of electrode plates extends perpendicular to an innerwall of the case.
 9. The oil level detecting device of claim 1, furthercomprising: a display operated by a control signal of the signalprocessor that visually or acoustically displays the oil level.
 10. Theoil level detecting device of claim 9, wherein the display comprises alight emitter that emits different colors according to a control signaloutput from the signal processor.
 11. The oil level detecting device ofclaim 1, wherein a flange is formed at an outer circumference of thesupporting portion, and wherein a flange seating portion, on which theflange is positioned, is formed at an outer circumference of themounting hole.
 12. The oil level detecting device of claim 1, whereinthe pins of the plurality of electrode plates extend perpendicular to awall surface of the case.
 13. The oil level detecting device of claim12, wherein the conductive plates of the plurality of electrode platesextend perpendicular to a wall surface of the case.
 14. The oil leveldetecting device of claim 1, wherein the pin is formed integral with theconductive plate.
 15. The oil level detecting device of claim 1, whereinthe conductive plate is formed wider than the pin.
 16. A compressorcomprising the oil level detecting device of claim
 1. 17. An airconditioner comprising the compressor of claim
 16. 18. The oil leveldetecting device of claim 1, wherein the conductive plates are spaced aprescribed distance from the wall surface of the case.
 19. The oil leveldetecting device of claim 1, wherein a width of the conductive plates isless than a width of the conductive plates and the mounting hole formedat the wall surface of the case.
 20. The oil level detecting device ofclaim 1, further comprises a microcomputer, wherein the microcomputercomprises: an input terminal electronically connected to the electronicelement for input of the at least one reference property; other inputterminal electronically connected to the detecting portion for input ofthe at least one property of the detecting portion; and an outputterminal that compares the at least one property of the detectingportion with the at least one reference property of the electronicelement and transfers a control signal to the controller.
 21. An airconditioner, comprising: a plurality of compressors comprising acompression device that introduces and compresses a working fluid, adriving device mechanically connected to the compression device thatoperates the compression device, a case that accommodates thecompression device and the driving device thereinside and having an oilstorage space that stores oil at a lower portion thereof, and an oillevel detecting device fixed to the case; an indoor device that performscooling or heating using refrigerant discharged from the plurality ofcompressors, the indoor device comprising an indoor heat exchanger andan expansion valve; and a controller that controls an operation of theplurality of compressors or the indoor device, wherein the oil leveldetecting device comprises: a detector comprising a supporting portionconfigured to be attached to the case and a detecting portion thatprotrudes inside the case, wherein at least one property of thedetecting portion varies according to an oil level within the case; anda signal processor comprising an electronic element having at least onereference property, the signal processor comparing the at least oneproperty of the detecting portion with the at least one referenceproperty of the electronic element and outputting a control signalaccording to the result, wherein the controller controls the operationof the plurality of compressors or the indoor device according to thecontrol signal transmitted from the signal processor to control the oillevel inside the case to be in an appropriate condition, wherein thesupporting portion comprises a supporting plate installed inside amounting hole formed at a wall surface of the case, and the detectingportion comprises a pair of electrode plates connected to the supportingplate, and wherein each of the plurality of electrode plates comprises:a conductive plate positioned at an inside of the oil storage space; anda pin that extends from the conductive plate to the supporting portionso as to electrically connect the conductive plate to the signalprocessor through the supporting plate, the pin being formed as a rigidbody, formed integral with the conductive plate, so as to support theconductive plate respective to the supporting plate.
 22. An oil leveldetecting device provided in a compressor, the compressor comprising acompression device that introduces and compresses a working fluid, adrive device mechanically connected to the compression device thatoperates the compression device, and a case that accommodates thecompression device and the driving device thereinside and having an oilstorage space that stores oil at a lower portion thereof, the oil leveldetecting device comprising: a detector comprising a supporting portionconfigured to be attached to the case of the compressor and a detectingportion that protrudes inside the case, wherein at least one property ofthe detecting portion varies according to an oil level inside the case;and a signal processor comprising an electronic element having at leastone reference property, that compares the at least one property of thedetecting portion with the at least one reference property of theelectronic element and outputs a control signal according to the result,wherein the supporting portion comprises a supporting plate installedinside a mounting hole formed at a wall surface of the case, and thedetecting portion comprises a pair of electrode plates connected to thesupporting plate, and wherein each of the pair of electrode platescomprises: a conductive plate positioned at an inside of the oil storagespace; and a pin that extends from the conductive plate to thesupporting portion so as to electrically connect the conductive plate tothe signal processor through the supporting plate, the pair ofconductive plate being disposed to be adjacent to each other having apredescribed spacing therebetween.
 23. An oil level detector fordetecting oil stored in an oil storage space in a case comprising: adetector having a support configured to be attached to the case of thecompressor and a pair of electrode plates configured to protrude intothe case, wherein at least one property of the pair of electrodes variesaccording to an oil level inside the case; and a signal processorconfigured to compare the at least one property of the pair ofelectrodes with at least one reference property and configured output acontrol signal according to the result, wherein the support includes asupport plate configured to be installed in a mounting hole formed at awall surface of the case, and the pair of electrode plates are connectedto the support plate, and each of the pair of electrode plates includes(i) a conductive plate positioned inside the oil storage space; and (ii)a pin extending from the conductive plate to the support to electricallyconnect the conductive plate to the signal processor, the pin beingformed as a rigid body so as to support the conductive plate to thesupporting plate.
 24. The oil level detector of claim 23, wherein the atleast one property of the detector corresponds to a capacitance of thedetector which varies according to the oil level, and at least onereference property comprises a predetermined capacitance.
 25. The oillevel detector of claim 23, wherein a flange is formed at an outercircumference of the support, and the mounting hole having a ledge toallow seating of flange on the ledge of the mounting hole.
 26. The oillevel detector of claim 23, wherein the pin and the conductive plate areconnected to each other by welding.
 27. The oil level detector of claim23, wherein the conductive plate is formed wider than the pin.
 28. Theoil level detector of claim 27, wherein larger surfaces of theconductive plates face each other.
 29. The oil level detecting device ofclaim 23, wherein the pair of electrode plates are spaced a prescribeddistance from each other.
 30. An oil level detector for detecting oilstored in an oil storage space of a case comprising: a detector having asupport configured to be attached to the case and a pair of electrodesconfigured to protrude inside the case, wherein at least one property ofthe detector varies according to an oil level inside the case; and asignal processor configured to compare the at least one property of thedetector with at least one reference property and configured output acontrol signal according to the result, wherein the support includes asupport plate installed in a mounting hole formed at a wall surface ofthe case, and the pair of electrode plates are connected to the supportplate, and each of pair of electrode plates includes (i) a conductiveplate positioned at an inside of the oil storage space; and (ii) a pinextending from the conductive plate to the support so as to support theconductive plate to the support plate, the pin is coupled to an outersurface of the conductive plate such that a first distance between thepair of conductive plates is less than a second distance between thepair of pins.
 31. The oil level detector of claim 30, wherein the pinand the conductive plate are connected to each other by welding.
 32. Theoil level detector of claim 30, wherein a width of the conductive plateis greater than a width of the pin.
 33. The oil level detector of claim30, wherein larger surfaces of the conductive plates face each other.34. An oil level detector for detecting oil stored in an oil storagespace of a case comprising: a detector having a support configured to beattached to the case and a pair of electrodes protruding inside thecase, wherein at least one property of the detector varies according toan oil level inside the case; and a signal processor configured tocompare the at least one property of the detecting portion with at leastone reference property and configured output a control signal accordingto the result, wherein the support includes a support plate installed ina mounting hole formed at a wall surface of the case, the pair ofelectrode plates are connected to the support plate, and at least one ofthe pair of electrode plates includes (i) a conductive plate positionedinside the oil storage space; and (ii) a pin extending from theconductive plate to the support to electrically connect the conductiveplate to the signal processor, the pin being formed as a rigid body soas to support the conductive plate to the support plate, and the pin andthe conductive plate are separate components which are connected to eachother.